GIS-Based Multi-Criteria Analysis for Rainwater Harvesting Suitability Mapping in Kamrup Metropolitan District, Assam

Abstract Assam experiences recurrent monsoon flood yet Kamrup Metropolitan District in Assam faces water scarcity due to rapid surface runoff, infiltration and inadequate rainwater storage and recharge practices. Increasing urbanization and building of impervious surfaces have further reduced the effective utilization of rainfall. The present study delineates rainwater harvesting suitability zones using a Geographic Information System (GIS) based multi-criteria decision analysis. The analysis was carried out considering rainfall, slope, drainage density, land use/land cover, soil type and elevation as major controlling parameters. All the six thematic layers were prepared, reclassified and assigned relative weights based on their hydrological influence. A weighted overlay analysis was carried out to integrate the thematic layers and generate the rainwater harvesting suitability map. The map categorizes the study area into high, moderate and low suitability zones. The areas with gentler slopes, permeable soils, lower drainage density and suitable land use conditions show higher potential for rainwater harvesting. The results show a clear spatial pattern with moderate rainwater harvesting suitability covering most of the central urban plain and higher suitability concentrated towards the eastern and southern parts of the Kamrup Metropolitan District. Keywords Kamrup Metropolitan, Rainwater Harvesting, GIS, Multi Criteria Decision Analysis, Weighted Overlay Analysis